1. Technical Field
The present invention relates to the technical field of safety systems and more particularly to a method and a system to be used in detecting attempts at malicious action against an installation under surveillance.
2. Description of the Related Art
As is well-known, it is becoming increasingly necessary to detect and signal in good time, for precautionary purposes, attempts at malicious action against installations of various types, such as enclosed areas, oil pipelines, gas pipelines or pipelines for fluid in general, connections for telecommunication networks or the distribution of electrical energy, airports, power stations, naval ports and other possible sensitive targets of various kinds. For example, in the specific case of oil pipelines, it has recently been observed, with ever increasing frequency, that said installations are subject to malicious action such as sabotage, tampering with the intent of stealing the product transported inside the pipeline, without excluding also possible terrorist attacks.
Said malicious actions can create serious damage both to the environment and to people, as well as causing considerable economic loss.
Some countries, given the frequency of said actions, sometimes resort to human patrolling of the pipelines along sections which can extend for hundreds of kilometers. However, this type of surveillance is very expensive and often not very effective.
Normally, said pipelines are further monitored by centralized systems which measure flow regularity and internal pressure. However, the disadvantage of these monitoring systems is that they signal any malicious action too late, often only after said action has been taken or completed.
Electronic systems using sensors or various kinds of transducers have been known and used for some time for the surveillance of installations. For example, surveillance systems using optical sensors, acoustic and seismic sensors, geophones, radio-frequency signal sensors, etc. are well-known.
Commonly, these systems are provided with processing units which receive signals provided by sensors and then process said signals in order to identify attempts at malicious action, such as entering into protected areas, trespassing, excavations and similar.
It has been observed that the reliability of the safety systems in the known art can be significantly conditioned by external disturbances, for example due to adverse environmental conditions or due to the passage of vehicles, animals or people near the areas to be protected. In fact, these disturbance factors can provoke inappropriate activation of said systems, generating alarm or improper signals.